i2c: hix5hd2: add i2c controller driver

I2C drivers for hix5hd2 soc series, including following chipset
Hi3716CV200, Hi3719CV100, Hi3718CV100, Hi3719MV100, Hi3718MV100.
Signed-off-by: Wei Yan <sledge.yanwei@huawei.com>
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
[wsa: folded dt docs into this patch]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Documentation/devicetree/bindings/i2c/i2c-hix5hd2.txt

+I2C for Hisilicon hix5hd2 chipset platform
+
+Required properties:
+- compatible: Must be "hisilicon,hix5hd2-i2c"
+- reg: physical base address of the controller and length of memory mapped
+     region.
+- interrupts: interrupt number to the cpu.
+- #address-cells = <1>;
+- #size-cells = <0>;
+- clocks: phandles to input clocks.
+
+Optional properties:
+- clock-frequency: Desired I2C bus frequency in Hz, otherwise defaults to 100000
+- Child nodes conforming to i2c bus binding
+
+Examples:
+I2C0@f8b10000 {
+	compatible = "hisilicon,hix5hd2-i2c";
+	reg = <0xf8b10000 0x1000>;
+	interrupts = <0 38 4>;
+	clocks = <&clock HIX5HD2_I2C0_RST>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+}

drivers/i2c/busses/Kconfig

@@ -77,6 +77,16 @@ config I2C_AMD8111
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-amd8111.
 
+config I2C_HIX5HD2
+	tristate "Hix5hd2 high-speed I2C driver"
+	depends on ARCH_HIX5HD2
+	help
+	  Say Y here to include support for high-speed I2C controller in the
+	  Hisilicon based hix5hd2 SoCs.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-hix5hd2.
+
 config I2C_I801
 	tristate "Intel 82801 (ICH/PCH)"
 	depends on PCI

drivers/i2c/busses/Makefile

@@ -48,6 +48,7 @@ obj-$(CONFIG_I2C_EG20T)		+= i2c-eg20t.o
 obj-$(CONFIG_I2C_EXYNOS5)	+= i2c-exynos5.o
 obj-$(CONFIG_I2C_GPIO)		+= i2c-gpio.o
 obj-$(CONFIG_I2C_HIGHLANDER)	+= i2c-highlander.o
+obj-$(CONFIG_I2C_HIX5HD2)	+= i2c-hix5hd2.o
 obj-$(CONFIG_I2C_IBM_IIC)	+= i2c-ibm_iic.o
 obj-$(CONFIG_I2C_IMX)		+= i2c-imx.o
 obj-$(CONFIG_I2C_IOP3XX)	+= i2c-iop3xx.o

drivers/i2c/busses/i2c-hix5hd2.c

+/*
+ * Copyright (c) 2014 Linaro Ltd.
+ * Copyright (c) 2014 Hisilicon Limited.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Now only support 7 bit address.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+/* Register Map */
+#define HIX5I2C_CTRL		0x00
+#define HIX5I2C_COM		0x04
+#define HIX5I2C_ICR		0x08
+#define HIX5I2C_SR		0x0c
+#define HIX5I2C_SCL_H		0x10
+#define HIX5I2C_SCL_L		0x14
+#define HIX5I2C_TXR		0x18
+#define HIX5I2C_RXR		0x1c
+
+/* I2C_CTRL_REG */
+#define I2C_ENABLE		BIT(8)
+#define I2C_UNMASK_TOTAL	BIT(7)
+#define I2C_UNMASK_START	BIT(6)
+#define I2C_UNMASK_END		BIT(5)
+#define I2C_UNMASK_SEND		BIT(4)
+#define I2C_UNMASK_RECEIVE	BIT(3)
+#define I2C_UNMASK_ACK		BIT(2)
+#define I2C_UNMASK_ARBITRATE	BIT(1)
+#define I2C_UNMASK_OVER		BIT(0)
+#define I2C_UNMASK_ALL		(I2C_UNMASK_ACK | I2C_UNMASK_OVER)
+
+/* I2C_COM_REG */
+#define I2C_NO_ACK		BIT(4)
+#define I2C_START		BIT(3)
+#define I2C_READ		BIT(2)
+#define I2C_WRITE		BIT(1)
+#define I2C_STOP		BIT(0)
+
+/* I2C_ICR_REG */
+#define I2C_CLEAR_START		BIT(6)
+#define I2C_CLEAR_END		BIT(5)
+#define I2C_CLEAR_SEND		BIT(4)
+#define I2C_CLEAR_RECEIVE	BIT(3)
+#define I2C_CLEAR_ACK		BIT(2)
+#define I2C_CLEAR_ARBITRATE	BIT(1)
+#define I2C_CLEAR_OVER		BIT(0)
+#define I2C_CLEAR_ALL		(I2C_CLEAR_START | I2C_CLEAR_END | \
+				I2C_CLEAR_SEND | I2C_CLEAR_RECEIVE | \
+				I2C_CLEAR_ACK | I2C_CLEAR_ARBITRATE | \
+				I2C_CLEAR_OVER)
+
+/* I2C_SR_REG */
+#define I2C_BUSY		BIT(7)
+#define I2C_START_INTR		BIT(6)
+#define I2C_END_INTR		BIT(5)
+#define I2C_SEND_INTR		BIT(4)
+#define I2C_RECEIVE_INTR	BIT(3)
+#define I2C_ACK_INTR		BIT(2)
+#define I2C_ARBITRATE_INTR	BIT(1)
+#define I2C_OVER_INTR		BIT(0)
+
+#define HIX5I2C_MAX_FREQ	400000		/* 400k */
+#define HIX5I2C_READ_OPERATION	0x01
+
+enum hix5hd2_i2c_state {
+	HIX5I2C_STAT_RW_ERR = -1,
+	HIX5I2C_STAT_INIT,
+	HIX5I2C_STAT_RW,
+	HIX5I2C_STAT_SND_STOP,
+	HIX5I2C_STAT_RW_SUCCESS,
+};
+
+struct hix5hd2_i2c_priv {
+	struct i2c_adapter adap;
+	struct i2c_msg *msg;
+	struct completion msg_complete;
+	unsigned int msg_idx;
+	unsigned int msg_len;
+	int stop;
+	void __iomem *regs;
+	struct clk *clk;
+	struct device *dev;
+	spinlock_t lock;	/* IRQ synchronization */
+	int err;
+	unsigned int freq;
+	enum hix5hd2_i2c_state state;
+};
+
+static u32 hix5hd2_i2c_clr_pend_irq(struct hix5hd2_i2c_priv *priv)
+{
+	u32 val = readl_relaxed(priv->regs + HIX5I2C_SR);
+
+	writel_relaxed(val, priv->regs + HIX5I2C_ICR);
+
+	return val;
+}
+
+static void hix5hd2_i2c_clr_all_irq(struct hix5hd2_i2c_priv *priv)
+{
+	writel_relaxed(I2C_CLEAR_ALL, priv->regs + HIX5I2C_ICR);
+}
+
+static void hix5hd2_i2c_disable_irq(struct hix5hd2_i2c_priv *priv)
+{
+	writel_relaxed(0, priv->regs + HIX5I2C_CTRL);
+}
+
+static void hix5hd2_i2c_enable_irq(struct hix5hd2_i2c_priv *priv)
+{
+	writel_relaxed(I2C_ENABLE | I2C_UNMASK_TOTAL | I2C_UNMASK_ALL,
+		       priv->regs + HIX5I2C_CTRL);
+}
+
+static void hix5hd2_i2c_drv_setrate(struct hix5hd2_i2c_priv *priv)
+{
+	u32 rate, val;
+	u32 scl, sysclock;
+
+	/* close all i2c interrupt */
+	val = readl_relaxed(priv->regs + HIX5I2C_CTRL);
+	writel_relaxed(val & (~I2C_UNMASK_TOTAL), priv->regs + HIX5I2C_CTRL);
+
+	rate = priv->freq;
+	sysclock = clk_get_rate(priv->clk);
+	scl = (sysclock / (rate * 2)) / 2 - 1;
+	writel_relaxed(scl, priv->regs + HIX5I2C_SCL_H);
+	writel_relaxed(scl, priv->regs + HIX5I2C_SCL_L);
+
+	/* restore original interrupt*/
+	writel_relaxed(val, priv->regs + HIX5I2C_CTRL);
+
+	dev_dbg(priv->dev, "%s: sysclock=%d, rate=%d, scl=%d\n",
+		__func__, sysclock, rate, scl);
+}
+
+static void hix5hd2_i2c_init(struct hix5hd2_i2c_priv *priv)
+{
+	hix5hd2_i2c_disable_irq(priv);
+	hix5hd2_i2c_drv_setrate(priv);
+	hix5hd2_i2c_clr_all_irq(priv);
+	hix5hd2_i2c_enable_irq(priv);
+}
+
+static void hix5hd2_i2c_reset(struct hix5hd2_i2c_priv *priv)
+{
+	clk_disable_unprepare(priv->clk);
+	msleep(20);
+	clk_prepare_enable(priv->clk);
+	hix5hd2_i2c_init(priv);
+}
+
+static int hix5hd2_i2c_wait_bus_idle(struct hix5hd2_i2c_priv *priv)
+{
+	unsigned long stop_time;
+	u32 int_status;
+
+	/* wait for 100 milli seconds for the bus to be idle */
+	stop_time = jiffies + msecs_to_jiffies(100);
+	do {
+		int_status = hix5hd2_i2c_clr_pend_irq(priv);
+		if (!(int_status & I2C_BUSY))
+			return 0;
+
+		usleep_range(50, 200);
+	} while (time_before(jiffies, stop_time));
+
+	return -EBUSY;
+}
+
+static void hix5hd2_rw_over(struct hix5hd2_i2c_priv *priv)
+{
+	if (priv->state == HIX5I2C_STAT_SND_STOP)
+		dev_dbg(priv->dev, "%s: rw and send stop over\n", __func__);
+	else
+		dev_dbg(priv->dev, "%s: have not data to send\n", __func__);
+
+	priv->state = HIX5I2C_STAT_RW_SUCCESS;
+	priv->err = 0;
+}
+
+static void hix5hd2_rw_handle_stop(struct hix5hd2_i2c_priv *priv)
+{
+	if (priv->stop) {
+		priv->state = HIX5I2C_STAT_SND_STOP;
+		writel_relaxed(I2C_STOP, priv->regs + HIX5I2C_COM);
+	} else {
+		hix5hd2_rw_over(priv);
+	}
+}
+
+static void hix5hd2_read_handle(struct hix5hd2_i2c_priv *priv)
+{
+	if (priv->msg_len == 1) {
+		/* the last byte don't need send ACK */
+		writel_relaxed(I2C_READ | I2C_NO_ACK, priv->regs + HIX5I2C_COM);
+	} else if (priv->msg_len > 1) {
+		/* if i2c master receive data will send ACK */
+		writel_relaxed(I2C_READ, priv->regs + HIX5I2C_COM);
+	} else {
+		hix5hd2_rw_handle_stop(priv);
+	}
+}
+
+static void hix5hd2_write_handle(struct hix5hd2_i2c_priv *priv)
+{
+	u8 data;
+
+	if (priv->msg_len > 0) {
+		data = priv->msg->buf[priv->msg_idx++];
+		writel_relaxed(data, priv->regs + HIX5I2C_TXR);
+		writel_relaxed(I2C_WRITE, priv->regs + HIX5I2C_COM);
+	} else {
+		hix5hd2_rw_handle_stop(priv);
+	}
+}
+
+static int hix5hd2_rw_preprocess(struct hix5hd2_i2c_priv *priv)
+{
+	u8 data;
+
+	if (priv->state == HIX5I2C_STAT_INIT) {
+		priv->state = HIX5I2C_STAT_RW;
+	} else if (priv->state == HIX5I2C_STAT_RW) {
+		if (priv->msg->flags & I2C_M_RD) {
+			data = readl_relaxed(priv->regs + HIX5I2C_RXR);
+			priv->msg->buf[priv->msg_idx++] = data;
+		}
+		priv->msg_len--;
+	} else {
+		dev_dbg(priv->dev, "%s: error: priv->state = %d, msg_len = %d\n",
+			__func__, priv->state, priv->msg_len);
+		return -EAGAIN;
+	}
+	return 0;
+}
+
+static irqreturn_t hix5hd2_i2c_irq(int irqno, void *dev_id)
+{
+	struct hix5hd2_i2c_priv *priv = dev_id;
+	u32 int_status;
+	int ret;
+
+	spin_lock(&priv->lock);
+
+	int_status = hix5hd2_i2c_clr_pend_irq(priv);
+
+	/* handle error */
+	if (int_status & I2C_ARBITRATE_INTR) {
+		/* bus error */
+		dev_dbg(priv->dev, "ARB bus loss\n");
+		priv->err = -EAGAIN;
+		priv->state = HIX5I2C_STAT_RW_ERR;
+		goto stop;
+	} else if (int_status & I2C_ACK_INTR) {
+		/* ack error */
+		dev_dbg(priv->dev, "No ACK from device\n");
+		priv->err = -ENXIO;
+		priv->state = HIX5I2C_STAT_RW_ERR;
+		goto stop;
+	}
+
+	if (int_status & I2C_OVER_INTR) {
+		if (priv->msg_len > 0) {
+			ret = hix5hd2_rw_preprocess(priv);
+			if (ret) {
+				priv->err = ret;
+				priv->state = HIX5I2C_STAT_RW_ERR;
+				goto stop;
+			}
+			if (priv->msg->flags & I2C_M_RD)
+				hix5hd2_read_handle(priv);
+			else
+				hix5hd2_write_handle(priv);
+		} else {
+			hix5hd2_rw_over(priv);
+		}
+	}
+
+stop:
+	if ((priv->state == HIX5I2C_STAT_RW_SUCCESS &&
+	     priv->msg->len == priv->msg_idx) ||
+	    (priv->state == HIX5I2C_STAT_RW_ERR)) {
+		hix5hd2_i2c_disable_irq(priv);
+		hix5hd2_i2c_clr_pend_irq(priv);
+		complete(&priv->msg_complete);
+	}
+
+	spin_unlock(&priv->lock);
+
+	return IRQ_HANDLED;
+}
+
+static void hix5hd2_i2c_message_start(struct hix5hd2_i2c_priv *priv, int stop)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	hix5hd2_i2c_clr_all_irq(priv);
+	hix5hd2_i2c_enable_irq(priv);
+
+	if (priv->msg->flags & I2C_M_RD)
+		writel_relaxed((priv->msg->addr << 1) | HIX5I2C_READ_OPERATION,
+			       priv->regs + HIX5I2C_TXR);
+	else
+		writel_relaxed(priv->msg->addr << 1,
+			       priv->regs + HIX5I2C_TXR);
+
+	writel_relaxed(I2C_WRITE | I2C_START, priv->regs + HIX5I2C_COM);
+	spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static int hix5hd2_i2c_xfer_msg(struct hix5hd2_i2c_priv *priv,
+				struct i2c_msg *msgs, int stop)
+{
+	unsigned long timeout;
+	int ret;
+
+	priv->msg = msgs;
+	priv->msg_idx = 0;
+	priv->msg_len = priv->msg->len;
+	priv->stop = stop;
+	priv->err = 0;
+	priv->state = HIX5I2C_STAT_INIT;
+
+	reinit_completion(&priv->msg_complete);
+	hix5hd2_i2c_message_start(priv, stop);
+
+	timeout = wait_for_completion_timeout(&priv->msg_complete,
+					      priv->adap.timeout);
+	if (timeout == 0) {
+		priv->state = HIX5I2C_STAT_RW_ERR;
+		priv->err = -ETIMEDOUT;
+		dev_warn(priv->dev, "%s timeout=%d\n",
+			 msgs->flags & I2C_M_RD ? "rx" : "tx",
+			 priv->adap.timeout);
+	}
+	ret = priv->state;
+
+	/*
+	 * If this is the last message to be transfered (stop == 1)
+	 * Then check if the bus can be brought back to idle.
+	 */
+	if (priv->state == HIX5I2C_STAT_RW_SUCCESS && stop)
+		ret = hix5hd2_i2c_wait_bus_idle(priv);
+
+	if (ret < 0)
+		hix5hd2_i2c_reset(priv);
+
+	return priv->err;
+}
+
+static int hix5hd2_i2c_xfer(struct i2c_adapter *adap,
+			    struct i2c_msg *msgs, int num)
+{
+	struct hix5hd2_i2c_priv *priv = i2c_get_adapdata(adap);
+	int i, ret, stop;
+
+	pm_runtime_get_sync(priv->dev);
+
+	for (i = 0; i < num; i++, msgs++) {
+		stop = (i == num - 1);
+		ret = hix5hd2_i2c_xfer_msg(priv, msgs, stop);
+		if (ret < 0)
+			goto out;
+	}
+
+	if (i == num) {
+		ret = num;
+	} else {
+		/* Only one message, cannot access the device */
+		if (i == 1)
+			ret = -EREMOTEIO;
+		else
+			ret = i;
+
+		dev_warn(priv->dev, "xfer message failed\n");
+	}
+
+out:
+	pm_runtime_mark_last_busy(priv->dev);
+	pm_runtime_put_autosuspend(priv->dev);
+	return ret;
+}
+
+static u32 hix5hd2_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+}
+
+static const struct i2c_algorithm hix5hd2_i2c_algorithm = {
+	.master_xfer		= hix5hd2_i2c_xfer,
+	.functionality		= hix5hd2_i2c_func,
+};
+
+static int hix5hd2_i2c_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct hix5hd2_i2c_priv *priv;
+	struct resource *mem;
+	unsigned int freq;
+	int irq, ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	if (of_property_read_u32(np, "clock-frequency", &freq)) {
+		/* use 100k as default value */
+		priv->freq = 100000;
+	} else {
+		if (freq > HIX5I2C_MAX_FREQ) {
+			priv->freq = HIX5I2C_MAX_FREQ;
+			dev_warn(priv->dev, "use max freq %d instead\n",
+				 HIX5I2C_MAX_FREQ);
+		} else {
+			priv->freq = freq;
+		}
+	}
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->regs = devm_ioremap_resource(&pdev->dev, mem);
+	if (IS_ERR(priv->regs))
+		return PTR_ERR(priv->regs);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq <= 0) {
+		dev_err(&pdev->dev, "cannot find HS-I2C IRQ\n");
+		return irq;
+	}
+
+	priv->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(&pdev->dev, "cannot get clock\n");
+		return PTR_ERR(priv->clk);
+	}
+	clk_prepare_enable(priv->clk);
+
+	strlcpy(priv->adap.name, "hix5hd2-i2c", sizeof(priv->adap.name));
+	priv->dev = &pdev->dev;
+	priv->adap.owner = THIS_MODULE;
+	priv->adap.algo = &hix5hd2_i2c_algorithm;
+	priv->adap.retries = 3;
+	priv->adap.dev.of_node = np;
+	priv->adap.algo_data = priv;
+	priv->adap.dev.parent = &pdev->dev;
+	i2c_set_adapdata(&priv->adap, priv);
+	platform_set_drvdata(pdev, priv);
+	spin_lock_init(&priv->lock);
+	init_completion(&priv->msg_complete);
+
+	hix5hd2_i2c_init(priv);
+
+	ret = devm_request_irq(&pdev->dev, irq, hix5hd2_i2c_irq,
+			       IRQF_NO_SUSPEND | IRQF_ONESHOT,
+			       dev_name(&pdev->dev), priv);
+	if (ret != 0) {
+		dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", irq);
+		goto err_clk;
+	}
+
+	pm_suspend_ignore_children(&pdev->dev, true);
+	pm_runtime_set_autosuspend_delay(priv->dev, MSEC_PER_SEC);
+	pm_runtime_use_autosuspend(priv->dev);
+	pm_runtime_set_active(priv->dev);
+	pm_runtime_enable(priv->dev);
+
+	ret = i2c_add_adapter(&priv->adap);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to add bus to i2c core\n");
+		goto err_runtime;
+	}
+
+	return ret;
+
+err_runtime:
+	pm_runtime_disable(priv->dev);
+	pm_runtime_set_suspended(priv->dev);
+err_clk:
+	clk_disable_unprepare(priv->clk);
+	return ret;
+}
+
+static int hix5hd2_i2c_remove(struct platform_device *pdev)
+{
+	struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&priv->adap);
+	pm_runtime_disable(priv->dev);
+	pm_runtime_set_suspended(priv->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int hix5hd2_i2c_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static int hix5hd2_i2c_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);
+
+	clk_prepare_enable(priv->clk);
+	hix5hd2_i2c_init(priv);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops hix5hd2_i2c_pm_ops = {
+	SET_PM_RUNTIME_PM_OPS(hix5hd2_i2c_runtime_suspend,
+			      hix5hd2_i2c_runtime_resume,
+			      NULL)
+};
+
+static const struct of_device_id hix5hd2_i2c_match[] = {
+	{ .compatible = "hisilicon,hix5hd2-i2c" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, hix5hd2_i2c_match);
+
+static struct platform_driver hix5hd2_i2c_driver = {
+	.probe		= hix5hd2_i2c_probe,
+	.remove		= hix5hd2_i2c_remove,
+	.driver		= {
+		.name	= "hix5hd2-i2c",
+		.pm	= &hix5hd2_i2c_pm_ops,
+		.of_match_table = hix5hd2_i2c_match,
+	},
+};
+
+module_platform_driver(hix5hd2_i2c_driver);
+
+MODULE_DESCRIPTION("Hix5hd2 I2C Bus driver");
+MODULE_AUTHOR("Wei Yan <sledge.yanwei@huawei.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:i2c-hix5hd2");